Resuscitating device



A. M. CAHAN 2,288,436

RESUSCITATING- DEVICE June 30, 1942.

Fild Oct. 5, 1941 2 Sheets-Sheet 1 49 mean 635 su 4 Y VACUUM wet ama- A7' ED CIRCUIT F02 SOLENOID uM A'h/ June 30, 1942, A. MI CAHAN 2,288,436

RESUSCITATING DEVICE Filed 001;. s, 1941 2 Sheets-Sheet 2 ATTOKNE Y5.

I Y INVENTOR.

Patented June 36,1942

, UNITED STATES PATENT OFFICE 2,288,436 RESUSCITA'IING DEVICE Alvin M.Cahan, New York, N. Y.

Application October 3, 1941, Serial No. 413,405

' 12 Claims. (01.128-29) My present invention relates to a resuscitatingdevice and while not limited thereto is especially adapted for use withany patientin whom there is respiratory failure, such as occurs infourth stage anaesthesia, gas poisoning, morphine poiwere not preventedby positive pressure anaesthesia.

The fire hazard entailed in the use of such an apparatus in conjunctionwith volatile explosive anaesthetics has been, eliminated by the use,instead of a system of mechanically operated electrical relays, whichwould'spark, of a vacuum tube amplifier relay system, whereby thecurrent passing across the electrical contacts is so small that nosparking can occur, and the machine can therefore be safely operatedeven in an atmosphere of cyclopropane and oxygen in their most explosiveproportions. Besides, the con trolling contacts are not in the stream ofgas, but are in a chamber separate from the gas channels. This may, ifdesired, be hermetically sealed, although this precaution isunnecessary.

The present invention aims to provide a device of the general characterindicated which is relatively simple in construction, easy andeconomical to fabricate and assemble, and admirably adapted for theperformance of the critical functions which his intended to carry out.

In the accompanying specification I shall describe and in the annexeddrawings show an illustrative embodiment of theresuscitating device ofthe present invention. It is, however, to be clearly understood that Ido not wish to be limited to the details shown inasmuch as changestherein may be made without the exercise of invention and within thescope of the claims hereto appended.

, In the accompanying drawings Figure 1 is a partiallyschematic. Prtially sectional view of a resuscitating device made in' accordancewith the principles of the present invention; and i p Figure 2 is aschematic showingof the electrical hookup employed in the vacuum tubeutilized as part of the combination of elements making up the presentinvention.

Before describing my invention in detail, I deem it advisable briefly toreferto some of the disadvantages existing in, devices hitherto employedfor corresponding purposes so that the manner in which the presentinvention overcomes and eliminates the same may be more readilyappreciated.

In positive pressure, and positive and negative pressure resuscitatingdevices now in use there is a tendency for the critical pressure thatthe lungs can withstand to be exceeded, so that I'have observed atautopsies done on infants that have died after "unsuccessful attemptsat'resuscitat'ion extensive emphysema of the lungs, both on crosssection, in the parenchyma of the lungs, and

subpleurally. Some of the subpleuralemphysl ematous blebs areoccasionally seen to be ruptured. In several adults that have died afterperiods of respiratory failure, during which time they had beenmaintained by positive and negative pressure resuscitation methods, Ihave observed that not only is there marked pulmonary emphysema thatdoes not occur otherwise in such patients, but in one case air hadactually been forced into the mediastinal connective tissue, and hadextended down along the paravertebral tissues. In the pulmonary veins ofthissame case was found considerable amounts of foam, shown by aerobicand anaerobic cultures not to be-due to gas. forming micro-organisms.The resuscitation devices used on these patients have been both manuallyand mechanically operated; each showing similar pathological results. Bymeans of the present invention, the instrument may be,

set' at the critical pressure, which will them not be exceeded duringthe resuscitating procedure. Other objects and advantages of the presentin- 'ention will readily occur to those skilled in the art to which thepresent invention relates as the detailed description thereofprogresses.

Referring now more in detailto the aforesaid illustrative embodiment ofthe present invention and with particular reference to the drawingsillustrating the same, it might be stated that the device comprises,enerally. three main operating units; a pressure-operatedcircuit-controlling device 5, a valve mechanism S, and a vacuum tuberelay device 1.

The pressure-operated circuit-controllingdevice 5 consists of acylindrical housing 8 which is open at its upper end and provided with acover plate 8 and-which is further provided in relay 6 the bottom wallthereof, with a vent ll. En,

closed within the housing 8 is a pressure operated bellows Ii, the lowerend of which is sealed to the bottom of the cylinder, but is opento thevent l and the upper end of which is secured to a plate I! from whichthere extends a rod it, the upper end of which is' covered by aninsulating cap l3. Secured to the cover plate 8 and depending tram-theunderside thereof into the housing 8 is an insulating block i4, whichsupports an intermediate spring contact l5, which T is bent seas to restagainst the insulating cap I II at the end of-rod' II atall times duringthe operation of the device, a lower spring contact i8 and an upperspring contact II. In order to ad- .iust the spacing between the threecontacts i5,

i6, and I! I provide adjusting screws i8 and i9 respectively providedwith insulating caps i8 and I8, the former operating upon the lowercontact It to determine that point to which the pressure in the systemmust fall before the circuit between contacts I! and I6 is made, and thelatter operating upon the contact i! to determine that point towhich thepressure must rise in order to close the circuit between contacts I 5and [1. Thus the upper and lower limits of pressure desired forresuscitation may .be selected by operating the machine againstavproperlyadapted water manometer, and the machine may thus bestandardized screws i8 and IS being provided with arrows, pointing topressures engravedon a dial placed at the periphery of the screws (notshown). The screws l8, and I! are stabilized by passage 23 which, ineilect, constitutes a continuation of the inlet passage 2i. Intermediatethe passages 2i and 23 I provide a plurality of.

vents 24 normally closed by a safety valve 25. For directly controllingthe flow of gas from passage 2i to passage 23 I provides sliding valveN.

The vacuum tube relay device 1, in and of itself,,is no part of thepresent invention. It is a unit that utilizes a well known electricalengineering circuit. For the purpose of describing its function in thepresent invention it is suihcient to say that the relay device 1includes a plurality of vacuum tubes, the operation of one or more ofwhichlis designed to excite another tube and deliver to its grid apositive charge which sets up a current through the solenoid 21,-thecurrent operating the solenoid continuing in flow until such time as thevacuum tube which controls the same, has delivered thereto a negativecharge, at which time the current through the solenoid is discontinuedand the solenoid permitted to return to its normal position.-

The three mechanisms are structurally connected with each other asfollows: 0

vSecured to the housing 8 of the circuit control device I is a tube 28,the upper end of which is sealed and the lower segment or whichcommunicates with the vent i0 and also with a flexible hose 2!, thelatter in turn being connected with an exhaust tube 20. Included in tube28 and adapted tocontrol the open cross-section thereof for a purposewhich will hereinafter be more iully set forth, is-a manually operatedgate valve I2. Adjacent the "closed upper end o thetube 28 I provide apassage It whereby the tube 28 connects with an inlet tube It providedat the upperend thereof with a delivery tube extension 35.

The lower end of the tube 34 is connected. with a flexible hose 36 inturn communicating-by means of a fitting 31 with the outlet passage 23-of the valve block 20.

The exhaust valve 3| is carried at one end ofa rocker arm 38 pivoted at39 to an'extension 40 formed on the valve block 20. The other end of thearm 38 is pivotally connected at. 4i to a link 42 attached to thesliding valve 26 and another link 43, an extension and part of therocker arm 38, pivotally connected at 44 to the core of the solenoid 21.Intermediate the valve block 20 and the rocker arm 38' on the exhaustvalve side thereof I provide a spring 45 which maintains the exhaustvalve 3! in the open position, and the intake valve 28, in the closedposition when the solenoid coil is not actuated by a.

erator, and in a more simplified fashion, if the I unit 5 beincorporated'on the same base as the valve mechanism 6 and the'vacuumtube relay circuit 1, modifying it, however, so that vent in,

connecting the interior of the bellows II with the gas supply, isconnected as a direct perpendicular extension from the intake 23. Thetubes 29 and 36 then are connected to a Y tube, (not shown), the thirdtube of this Y tube then delivering the gaseous mixture to the patient,and returning it to the machine. It should be noted that with thisarrangement the intake tube '36 should be of larger diameter so as todecrease the pressure gradient to an inconsequential level at the maxi--mum rate of flow of the gas. 1

The various mechanisms are electrically con- I nected with each other asfollows:

The numerals 4? and 48 designate the main supply line for a source ofelectrical current.

These leads enter the vacuum tube relay 1. The

relay is connected by conductors 49 and It to the solenoid 2! and thevarious circuits which control the supply of current to the solenoid 21are completed by means of conductors SI, 52 and 53, the first of theseconductors ng connected with the intermediate contact it, e second ofthe transformer as is tapped to suppl current to the filament ofarectifier tube 51, the two plates of which are likewise supplied withcurrent from the secondary of the transformer 55. Associated with therectifier i! is a filter, comprising the resistors 88, 58 and M and thecondensers Cl, 82 and '68, which, in turn, is elec-=' trically connectedthrough resistors 64 to It inelusive, with two high-mu tubes I4 and II.It will be ,noted that the electrical connections are such that thetubes 14 and" cannot bothbe conducting at the same time; only one orthe,

other can be so functioning at any given time.

The tubes 14 and 15 are respectively connected with the upper and lowercontacts II and I6 of the pressure operated circuit-control by means ofthe conductors 53 and 52 and are also connected with the intermediatecontact I5 01 said control by means of the conductors.

The secondary of the transformer 56 supplies unrectified alternatingcurrent to another vacuum tube 16 and, through the conductors 49 and 50to the solenoid 21.

Thus, when the contacts l5 and I6 are engaged, the tube becomesconducting and the tube 14 does notconduct so that the tube 16 permitsthe passage of current to the solenoid 21. When there is engagementbetween the contacts I 5 and H, the tube 15 ceases to conduct and thetube 14 becomes conducting. The potential drop due to the anode currentf this tube.

flowing through the resistors 61 and 68 provides a negative voltagebetween the grid and cathode of the tube 16 thus stopping the passage ofcurrent to the solenoid.

This completes the description of the aforesaid illustrative embodimentof the device of the present invention and the mode of operation and usethereof may be briefly summarized as follows:

Assuming that the device is to be used for resuscitation, the hose 46 isconnected with a source of oxygen, as described above. First the oxygensupply is turned on to deliver the desired flow per minute, which isgauged by the requirements of the patient-adult or infant. The currentsupplying the vacuum tube circuit is turned on. Since the pressure inthe tube supplying the gas to the patient is atmospheric, contacts l5and iii are together, and when the vacuum tubes become heated and beginto function, the solenoid coil is activated, the core is drawn into theaxis of the coil, thus opening valve 253, allowing the gas to flow alongtube 36 toward the patient, and simultaneously closing valve 3 5, thusshutting off the exhalation valve. The tube 323 may then be connectedwith a tracheal airway already in place in the patient, or with a rigidface mask, fastened over the patients nose'and mouth in the standardmanner used with closed system anaesthesia. The gas enters the patientslungs and expands them up to the predetermined level at which time aback pressure is built up in the extensiontfi, which back pressure iscommunicated by way of the vent 33 to the outlet tube 28 which in turnconveys the built up pressure by way of vent Hi to the bellows H. Whenthis pressure rises above the predetermined min" imai pressure (inactual trials this has been of the order of 1 and 2 millimeters of waterpressure), the bellows H expands so as to move the plate I2, and with itthe rod 13, upwardly in the cylinder 8, so as to break the contactbetween I6 and 15. However, notwithstanding the breaking of the circuitthrough the contacts 15 and Hi, the relay I, originally operated byreason of the engagement between the contacts l5 and I6, maintains thesupply of current through the solenoid 21 to keep the valve 25 open andthe valve 3| closed. However, as the pressure operating upon the bellowsl I increases, another criticalpoint is reached and at the instant thatthis point is reached a new circuit is established by reason of theengagement between the intermediate contact l5 and the upper contact II.This circuit through the relay 1, delivers a negative charge to thevacuum tube controlling the flow of current through the solenoid 21 andthis negative charge brings about cessation of current operating thesolenoid 21 so that the spring 45 can then function to pivot the rockerarm 38 thereby closing the inlet valve 26 and'opening the exhaust valve3|. This operation results in a reduction of pressure throughout thesystem with the result that the bellows ll moves toward its collapsedposition. The movement of the bellows must be gradual rather than suddeninasmuch as a sudden drop of the bellows results in vibrations whichwill move the contact I 5 rapidly into and out of engagement with thecontacts l6 and i1, thus interfering with the proper operation of thedevice. In order to prevent this sudden drop in pressure, the valve 32must be adjusted so, that rate of expiration of the patient, caused bythe collapse of his naturally elastic lungs, just filled by theresuscitator will maintain intratracheal pressures within the exhalationtube, and thus within the control bellows ,l I. This will vary fromadult to infant, and therefore the valve must be marked for threepositions corresponding to the tidal respiratory exchange from adult toinfant. Thus, the valve 32 is capable of adjustment so that the crosssection of its airway can be made to correspond with the cross sectionof the trachea of the patient being treated. Inasmuch as there is littlevariation in the cross sectional area of newborn infants (for practicalpurposes)? chiidren, and adults, a suitable scale may be constructed forthe operation of this valve. Inthis way, the lungs of the patient willbe allowed to collapse at their natural free rate. As soon as thepressure in the system as a whole begins to reduce from the uppercritical limit, the contact is becomes disengaged from the contact i l,but this has no eifect upon the circuits set up in the relay l tocontrol the solenoid 2i inasmuch as again another holding tube in thecircuit of the relay 1 continues to function under its negative chargeuntii such time as the pressure in the systemas a whole is reduced tothe lower critical point, at which time contact is re-establishedbetween the contacts l5 and I6 and the "holding tube of the relay '5 isagain supplied with a positive charge. This results in a repetition ofall of the operations just described and these operations are continueduntil such time as the patient being operated upon is able to breathe ofhis own volition. The device is then withdrawn from the patient.

This completes the description of the mode of operation and use of thedevice of the present invention. As stated above, instead of oxygenbeing supplied through the hose 46, the latter can be connected with asource of general anesthetic and the device used just as efficiently forthis function in properly selected cases.

It will be noted from all of the foregoing that the resuscitating deviceof the present invention is simple in construction, easy and economicalto fabricate and assemble and admirably adapted to perform the intendedfunction reliably.

What I claim as my invention is: 1. In a device of the characterdescribed, an intake conduit for conveying a gas'to a personstrachealpassage, an exhaust conduit communicating with said intakeconduit and also with a the atmosphere, inlet and outlet valves for saidintake and exhaust conduits, electro-magnetic means for operating saidinletand outlet valves,

a vacuum tube operated'triggermechanism for controlling the operation ofsaid electro-magnetic means and means, communicating with said exv letand outlet valve-operating means, said means take and exhaust conduits,a solenoid for operating said inlet and outlet valves, and means,communicating with said exhaust conduit and responsive to predeterminedupper and lower pressure limits within the entire system, forestablishing a plurality of electrical circuits to control thefunctioning of said solenoid whereby a flow of current thereto isinitiated when the pressure reaches the lower limit and is maintainedtherein until the pressure reaches the upper limit, when said flow of.current is discontinued and remains so until the pressure returns tothe lower limit.

including a plurality of electrical contacts and a bellows connectedwith one of said contacts and adapted to move the same into and out ofelectrical engagement with the remaining contacts.

.6. In a device of the character described, an intake conduit forconveying a gas to a persons tracheal passage, an exhaust conduitcommunicatingwith said intake conduit and also with the atmosphere,inlet and outlet valves for said. intake and exhaust conduits,electro-magnetic means for operating said inlet and outlet valves, avacuum tube operated trigger mechanism for controlling the operation ofsaid electrd-magnetic means and means, communicating with said exhaustconduit and responsive to predetermined upper and'lower pressure limitswithin the eni tire system. for establishing a plurality of elec- 3. Ina device of the characterdescribe'd, an

. limits within the entire system, for establishing a plurality ofelectrical circuits through said trigger mechanism to. control thefunctioning of said electro-magnetic inlet and outlet valve-operatingmeans. I

4. In a device of the character described, an intake conduit forconveying a gas to a persons tracheal passage. an exhaust conduitcommunieating with said intake conduit and also with the atmosphere.inlet and outlet valves for said intake and exhaust conduits, a solenoidfor operating said inlet and outlet valves, and bellowsoperated means,communicating with said exhaust conduit and responsive to predeterminedupper and lower pressure limits within the entire system, forestablishing a plurality of electrical circuits to control thefunctioning of said solenoid whereby a flow of current thereto isinitiated when the pressure reaches the lower limit and is maintainedtherein until the prestrical circuits through said trigger mechanism tocontrol the functioning of said electro-magnetic inlet and outletvalve-operating means, said means including a plurality of electricalcon tacts, a bellows connected with one of said contacts and adapted tomove the same into and out of electrical engagement with the remainingcontacts, and means to adjust the amounts of pressure necessary toconsummate said electrical engagements. I

'7. In a device of the character described, an intake conduit forconveying a gas to a persons tracheal passage, an exhaust conduitcommunicating with said intake conduit and also with sure reaches theupper limit, when said flow of current is discontinued and remains sountil the pressure returns to the lower limit.

5. In a device of the character described, an intake conduit forconveying a gas to a persons tracheal passage, an exhaust conduitcommunicating with said .intake conduit and also with the atmosphere,inlet and outlet valves iorsaid intake and exhaust conduits, electro-magnetic means for operating said inlet and outlet valves, a vacuumtube operated trigger mechanism for controlling the operation of saidelectro-magnetic means and means, communicating with said exhaustconduit'and responsive to predetermined upper and lower pressure limitswithin the entire system, for establishing a plurality of electricalcircuits through said trigger mechanism to control the functioning ofsaid electro-magnetic inthe atmosphere, inlet and outlet valves for saidintake and exhaust conduits, a solenoid for operating said inlet andoutlet valves, and means, communicating with said exhaust conduit andresponsive to predetermined upper and lower pressure limits within theentire system,'for establishing a plurality of electrical circuits to.control the functioning of said solenoid whereby a flow of currentthereto is initiated when the pressure reaches the lower limit and ismaintained therein until the pressure reaches the upper limit, when saidflow of current is discontinued and remains so untilthe pressure returnsto the lower limit, said means including a plurality of electricalcontacts, and a bellowsconnected with one 'of said contacts and adaptedto move the same intoand out of electrical en- 7 gagement with theremaining contacts.

8, In a device of the character described, an intake conduit forconveying a gas to a persons tracheal passage, an exhaust conduitcommunicating with said intake conduit and also with the atmosphere,inlet and outlet valves for said intake and exhaust conduits, a solenoidfor operating said inlet and outlet valves, and means, communicatingwith said exhaust conduit and responsive to predetermined upper andlower pressure limits within the entire system, for establishing aplurality of electrical circuits to 1 control the functioning of saidsolenoid whereby a flow of current thereto isinitiated when the pressurereaches the lower limit and is maintained therein until the pressurereaches the upper limit, when said flow of current is discontinued andremains so until the pressure returns to the lower limit,'said meansincluding a plurality of electrical contacts, a bellows connected withone of said contacts and adapted to move the same into and out ofelectrical engagement with the remaining contacts, and means to adjustthe amounts of pressure necessary to consummate said electricalengagements.

9. In a device of the character described an intake conduit forconveying a gas to a person's tracheal passage, an exhaustconduit'communieating with said intake conduit and also with theatmosphere, inlet and outlet valves for said intake and exhaustconduits, electro-magnetic means for operating said inlet and outletvalves, a vacuum tube operated trigger mechanism for controlling theoperation of said ,electro-magnetic means and means, communicating withsaid exhaust conduit and responsive to predetermined upper and lowerpressure limits within the entire system, for establishing a pluralityof electrical circuits through said trigger mechanism to control thefunctioning oi! said electro-magnetic means whereby a flow of currentthereto is initiated when the pressure reaches the lower limit and ismaintained therein until the pressure reaches the upper limit, when saidflow of current is discontinued and remains so until thepressure returnsto the lower limit.

10. In a device oi. the character described, an intake conduit forconveying a gas to a person's tracheal passage, an exhaust conduitcommunicating with said intake conduit and also with the atmosphere,inlet and outlet valves for said intake and exhaust conduits,electro-magnetic means for operating said inlet and outlet valves,

a vacuum tube operated trigger mechanism i'or controlling the operationof said electro-magnetic means and bellows-operated means, communicatingwith said exhaust conduit and responsive tracheal passage, an exhaustconduit communicating with said intake conduit and also with theatmosphere, inlet and outlet valves for said intake and exhaustconduits, electro-magnetic means for operating said inlet and outletvalves, a vacuum tube operated trigger mechanism for controlling theoperation of said electro-magnetic means and means, communicating withsaid exhaust conduit and responsive to predetermined upper and lowerpressure limits within the entire system, for establishing a pluralityof electrical circuits through said trigger mechanism to control thefunctioning of said electro-magnetic means whereby a flow of currentthereto is inieating with said intake conduit and also with I theatmosphere, inlet and outlet valves for said intake and exhaustconduits, electro-magnetic means, for operating 'said inlet and outletvalves, a vacuum tube operated trigger mechanism for controlling theoperation oi said electro-magnetic means and means communicating withsaid exhaust conduit and responsive to predetermined upper and lowerpressure limits within the ,en-

I ments.

tire system, for establishing a plurality of electrical circuits throughsaid trigger mechanism to control the functioning of saidelectro-magnetic means whereby a flow of current thereto is initiatedwhen the pressure reaches the lower limit and is maintained thereinuntil the pressure,

ALVIN M. CAHAN.

